Mount Rushmore National Memorial in Keystone, South Dakota, was carved on the granite face of a mountain in the Black Hills between 1927 and 1941. Funding problems made the project take longer than was originally expected. Mount Rushmore pays patriotic tribute to four United States presidents—George Washington, Thomas Jefferson, Theodore Roosevelt, and Abraham Lincoln—with 60-foot-tall faces carved into a mountainside in the Black Hills.

Source: National Geographic